The invention relates to hot melt inks.
Hot melt inks are solid at room temperature and liquid at temperatures above room temperature. Hot melt inks can be used, for example, in ink jet printing. During ink jet printing, the ink is heated so that it becomes liquid, then is ejected through a printhead onto a substrate. The ink then solidifies on the substrate.
Hot melt inks have been used in a variety of applications, including printing screen manufacturing processes. During such processes, a printing screen is coated with a layer of ultraviolet (UV) curable material; a hot melt ink is then applied to parts of the UV curable layer. The screen is then exposed to UV light. The hot melt ink provides a UV opaque "mask" that prevents the material covered by the mask from being cured by the UV light.
At the end of the manufacturing process, the uncured material, as well as the ink mask, are removed by washing the screen with water. Often, extended washing processes are required. In addition, the ink typically falls off the screen in large clumps or flakes during the washing processes. These large pieces can lead to problems because they can redeposit on the screen and can clog the filters of the equipment used to perform the washing procedure.